Customers Who Never Order

  • Problem
    Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything.
    Table: Customers.
    +----+-------+
    | Id | Name |
    +----+-------+
    | 1 | Joe |
    | 2 | Henry |
    | 3 | Sam |
    | 4 | Max |
    +----+-------+
    Table: Orders.
    +----+------------+
    | Id | CustomerId |
    +----+------------+
    | 1 | 3 |
    | 2 | 1 |
    +----+------------+
    Using the above tables as example, return the following:
    +-----------+
    | Customers |
    +-----------+
    | Henry |
    | Max |
    +-----------+

  • Code

Write your MySQL query statement below

select Name from Customers where Id not in (select * from(select CustomerId from Orders) t)

select c.Name from Customers c left join Orders o on c.id = o.CustomerId where o.CustomerId is NULL

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